Sperchon himalayus, Pesic, Vladimir & Smit, Harry, 2007

Pesic, Vladimir & Smit, Harry, 2007, First records of water mites (Acari: Hydrachnidia) from Bhutan, with description of two new species, Zootaxa 1613, pp. 45-56 : 46-47

Sperchon himalayus sp. nov.

(Figs. 1–7)

Type series. Holotype: female ( ZMAN), dissected and slide mounted in Hoyer's fluid. Bhutan: Dochu La, 06.iv.2002, 2800 m asl.

Diagnosis. Integument striated; coxal surface reticulated; P-3 longer than the P-4, P-4 ventral setae widely separated, anterior ventral seta situated near middle of the segment; the claw with two clawlets.

Description

Female: Idiosoma (ventral view: Fig. 1; dorsum not in a suitable position to illustrate) L 1131, W 887. Integument striated. Only five pairs of small plates on dorsum.

Anterior coxae lying close to each other, but not fused. Posterior groups of coxae widely separated; L between anterior end of first coxae and posterior end of fourth coxae 506; surface of coxae reticulated; glandularia Cxgl-4 open on Cx-3. Setae Vgl-1 without accompanying glandularia, on very small sclerites. Excretory pore smooth. One pair of small ventral plates.

External genital organ lying between posterior coxae; genital valves not covering the genital acetabula; posterior acetabula rounded; middle acetabula largest; L of genital valves 168, W 36; L of acetabula 1–3: 61- 67-50.

Capitulum (Fig. 7) with long rostrum, L 247; chelicera ( Fig. 8 ) L 303, basal segment L 253, claw L 72, ratio chelicerae basal segment/claw L 3.5; palp (Figs. 4–5) total L 474, dL and %L (in parentheses, given as % of total L): P-1 26 (5.5), P-2 113 (23.8), P-3 164 (34.6), P-4 150 (31.7), P-5 21 (44.3); P-2/P-4 ratio 0.75; P-2 with long ventrodistal projection bearing two small and one long setae; P-3 longer than P-4; P-4 anterior ventral seta situated near middle of the segment, posterior ventral seta approaching the distoventral margin of the segment.

Third-fifth segments of leg IV (Fig. 3) and III and fourth-fifth segments of leg II with longitudinal rows of rather long plumose setae. L of leg segments: I – 56, 67, 97, 134, 150, 141; II – 66, 76, 116, 172, 188, 178; III – 77, 84, 125, 200, 219, 197, IV – 147, 125, 153, 263, 263, 219. Ambulacrum (Fig. 2) with claw blade slightly protruding, claw with two clawlets, claw and clawlets of equal length, but claw thicker.

Discussion. The majority of Sperchon species have a claw with one clawlet. In several species, however, the claws have two clawlets. Due to the striated integument and the presence of glandularia on Cx-3, S. himalayus sp. nov. is similar to S. minor Tuzovskij (Central Asia) from which it is easily distinguishable by the following characters (in parentheses data from Tuzovskij 2003): P-2 with long ventrodistal projection bearing setae (small ventrodistal projection without setae), P-3 with a straight ventral margin, longer than P-4 (P-3 with convex ventral margin, shorter than P-4); P-4 ventral setae widely separated, anterior ventral seta situated near middle of the segment (ventral setae situated close to each other in the distal part of P-4); the capitulum with a long rostrum (short rostrum); the basal segment of chelicera elongated (the basal segment shortened and large); coxal plates reticulated (coxal plates not reticulated), excretory pore smooth (surrounded by sclerotized ring).

Etymology. The species is named after the Himalayas where it was collected.

Distribution. Known only from the type locality in Bhutan.

Biology. Sperchon himalayus sp. nov. is probably a rhitrobiontic species.

– Sperchon himalayus , female: 1 = idiosoma, ventral view; 2 = claw; 3 = IV–L; 4 = chelicera; 5 =

palp, lateral view; 6 = palp, medial view; 7 = capitulum. Scale bars = 100 m.

Figures

FIGURES 8 – 14. Sperchon cf. indicus Kumar et al., female: 8 = idiosoma, dorsal view; 9 = idiosoma, ventral view; 10 = IV – L- 3 – 6; 11 = claw; 12 = palp, medial view; 13 = capitulum; 14 = chelicera. Scale bars = 100 m.